GB2574338A - Electrical protection device and method of operation - Google Patents

Electrical protection device and method of operation Download PDF

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Publication number
GB2574338A
GB2574338A GB1910596.4A GB201910596A GB2574338A GB 2574338 A GB2574338 A GB 2574338A GB 201910596 A GB201910596 A GB 201910596A GB 2574338 A GB2574338 A GB 2574338A
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GB
United Kingdom
Prior art keywords
electrical
neutral
protection device
live
earth
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB1910596.4A
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GB201910596D0 (en
GB2574338B (en
Inventor
Louden Ian
James Walden Robert
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Pod Point Ltd
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Pod Point Ltd
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Filing date
Publication date
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Priority to GB1910596.4A priority Critical patent/GB2574338B/en
Publication of GB201910596D0 publication Critical patent/GB201910596D0/en
Publication of GB2574338A publication Critical patent/GB2574338A/en
Application granted granted Critical
Publication of GB2574338B publication Critical patent/GB2574338B/en
Active legal-status Critical Current
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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/14—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to occurrence of voltage on parts normally at earth potential
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/24—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to undervoltage or no-voltage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/04—Cutting off the power supply under fault conditions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/60—Monitoring or controlling charging stations
    • B60L53/62—Monitoring or controlling charging stations in response to charging parameters, e.g. current, voltage or electrical charge
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
    • H02H3/265—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents responsive to phase angle between voltages or between currents
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
    • H02H5/10—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to mechanical injury, e.g. rupture of line, breakage of earth connection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
    • H02H5/10—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to mechanical injury, e.g. rupture of line, breakage of earth connection
    • H02H5/105—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to mechanical injury, e.g. rupture of line, breakage of earth connection responsive to deterioration or interruption of earth connection
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/12—Electric charging stations

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

An electrical protection device 300 controls electrical power from a mains power source 314 to an electrical apparatus such as an electric vehicle 206 or other outdoor electrical load. The electrical protection device 300 includes a matrix switching arrangement 212 whose power switches 308, 310, 312 are controlled from a data processing arrangement 216. The electrical power is coupled from the electrical protection device 300 to the electrical apparatus 206 via at least live 302, neutral 304 and earth 306 conductors. The data processing arrangement 216 senses a voltage difference between the live 302 and neutral 304 conductors, and switches the switching matrix 212 to disconnect the live 302, neutral 304 and earth 306 conductors coupled to the electrical apparatus 206 in an event that the voltage difference reduces below a threshold voltage in magnitude. The data processing arrangement 216 may also switch the switching matrix 212 to disconnect the electrical apparatus 206 if the voltage difference between neutral 304 and earth 306 conductors exceeds a threshold or if a phase difference between live 302 and neutral 304 conductors exceeds a threshold or if a rate of change of phase difference between live 302 and neutral 304 conductors exceeds a threshold.

Description

ELECTRICAL PROTECTION DEVICE AND METHOD OF OPERATION
TECHNICAL FIELD
The present disclosure relates to electrical protection devices that are coupled, when in use, between electrical apparatus and sources of electrical power, for example electrical power networks (namely, electrical power grid}, wherein the sources of electrical power provide electrical power to the electrical apparatus, and wherein the electrical protection devices provide fault protection to the electrical apparatus. For example, the electrical apparatus includes various outdoor electrical appliances, outdoor electrical vehicle recharging systems (to recharge battery arrangements of the electrical vehicles) and so forth. Moreover, the present disclosure relates to methods for (of) operating the aforementioned electrical protection devices. Furthermore, the present disclosure relates to software products that are executable on computing hardware of the aforesaid electrical protection devices for implementing aforesaid methods.
BACKGROUND
In known electrical apparatus, it is contemporary practice to employ various known types protection devices such as fuses and circuit breakers, because electrical power dissipated in an unintentional manner in the electrical apparatus can be potentially hazardous to users and can also result in fires being initiated. However, the known protection devices are not able to provide protection for all feasible fault conditions, and therefore do not provide comprehensive user protection.
-2A more advanced form of protection device is described in a published PCT application W02010/113927A1 (Electric Vehicle Charger and Ground Fault Detection Method·, applicant - The Tokyo Electric Power Corporation Inc.); there is described an electrical vehicle charger that is capable of, while rapidly charging a given electrical vehicle, detecting both an occurrence of a ground fault in the electrical vehicle charger and an occurrence of electrical leakage in the given electrical vehicle. To provide data communication with the electrical vehicle during charging thereof, a communication earth wire is employed to connect a negative electrode of a control system power supply of the electrical vehicle charger to the given vehicle's body earth that is grounded to an Earth reference potential via a ground wire. A ground fault detection device of the electrical vehicle charger includes a series circuit of resistors having same resistance values that are connected to a positive electrode-side charging line and a negative electrode-side charging line, a ground wire for connecting a point between the resistors to the Earth reference potential, a current detector for sequentially outputting measured values of DC current flowing through the ground wire, and a controller for detecting an occurrence of a ground fault in the electric vehicle charger and an occurrence of leakage in the electrical vehicle by comparing the measured current values output by the current detector with a threshold value. However, use of such a known approach pertinent for DC chargers for electrical vehicles in countries that employ a floating AC connection regime is unsuitable. When AC supplies are employed in association with electrical vehicle chargers, it is customary for electrical vehicles to include AC-to-DC inverters thereon to provide a DC supply for recharging batteries.
Whereas the published PCT application W02010/113927A1 relates to a power grid that pertains in Japan, such a system is not appropriate for
-3use in a form of electrical power grid as provided in the United Kingdom, for example, wherein particular types of hazardous conditions can arise.
SUMMARY
The present disclosure seeks to provide an improved electrical protection device for use with an electrical apparatus, for example an outdoor appliance such as power tools, electric lawnmowers, lighting fixtures, electrical heaters, air conditioning units, electrical vehicle charging systems, but not limited thereto. The present disclosure also seeks to provide an improved method for operating the improved electrical protection device. An aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in prior art, and to provide an improved protection device that efficiently detects faults.
In one aspect, the present disclosure provides an electrical protection device that, when in operation, controls electrical power coupled therethrough to an electrical apparatus, wherein the electrical protection device includes a matrix switching arrangement whose power switches are controlled from a data processing arrangement, wherein electrical power is coupled from the electrical protection device to the electrical apparatus via at least LIVE, NEUTRAL and EARTH conductors, and wherein the data processing arrangement senses, when in operation, a voltage difference between the LIVE and NEUTRAL conductors, and switches the switching matrix arrangement to disconnect the LIVE, NEUTRAL and EARTH conductors coupled to the electrical apparatus in an
-4event that the voltage difference reduces below a threshold voltage (Vth) in magnitude.
Optionally, the electrical apparatus is an electrical vehicle and the electrical protection device is included within an electrical vehicle charging system; the electrical protection device, when in operation, controls electrical power coupled therethrough to the electrical vehicle to charge a battery arrangement of the electrical vehicle.
Optionally, the electrical protection device is arranged in a manner wherein the data processing arrangement, when in operation, senses (determines) a voltage difference between the NEUTRAL and EARTH conductors, and switches the matrix switching arrangement to disconnect the power switches coupled to the electrical vehicle in an event that the voltage difference increases above an earth threshold voltage (Vet) in magnitude.
Optionally, in an event that a phase angle difference between LIVE and NEUTRAL conductors in the electrical protection device exceeds a phase threshold (Θτη) or a rate of change of the phase angle difference exceeds a phase change rate threshold, or both, the switching matrix arrangement is used to disconnect LIVE, NEUTRAL and EARTH conductors to the electrical apparatus, in an event of one or more of such phase thresholds being exceeded.
In another aspect, the present disclosure provides a method for (of) operating an electrical protection device that, when in operation, controls electrical power coupled therethrough to an electrical apparatus, characterized in that the method includes:
(i) arranging for the electrical protection device to include a matrix switching arrangement whose power switches are controlled from a data processing arrangement;
(ii) arranging for electrical power to be coupled from the electrical protection device to the electrical apparatus via at least LIVE, NEUTRAL and EARTH conductors; and (iii) arranging for the data processing arrangement to sense, when in operation, a voltage difference between the LIVE and NEUTRAL conductors, and switching the switching matrix arrangement to disconnect the LIVE, NEUTRAL and EARTH conductors coupled to the electrical apparatus in an event that the voltage difference reduces below a threshold voltage (Vet) in magnitude.
Optionally, the method includes arranging for the electrical apparatus to be an electrical vehicle, and arranging for the electrical protection device to be included in an electrical vehicle charging system; the electrical protection device, when in operation, controls electrical power coupled therethrough to the electrical vehicle to recharge a battery arrangement of the electrical vehicle.
Optionally, the method includes arranging for the data processing arrangement, when in operation, to sense (determine) a voltage difference between the NEUTRAL and EARTH conductors, and to switch the matrix switching arrangement to disconnect the power switches coupled to the electrical apparatus in an event that the voltage difference increases above an earth threshold voltage (Vet) in magnitude.
Optionally, the method includes sensing (detecting) a phase angle difference between LIVE and NEUTRAL conductors in the electrical protection device exceeding a phase threshold (Θτη) or a rate of change of the phase angle difference exceeding a phase change rate threshold, or both, wherein the switching matrix arrangement is used to disconnect
-6LIVE, NEUTRAL and EARTH conductors to the electrical apparatus in an event of one or more of such phase thresholds being exceeded.
In this disclosure, ^substantially means within a range of 85% to 115% of a given value, more optionally within a range if 95% to 105% of the given value.
In yet another aspect, there is provided computer program product comprising a non-transitory computer-readable storage medium having computer-readable instructions stored thereon, the computer-readable instructions being executable by a computerized device comprising processing hardware to execute the aforementioned methods.
It will be appreciated that the systems and methods are configured to detect the threshold voltage Vth being exceeded, and to use the switching matrix arrangement to disconnect LIVE, NEUTRAL and EARTH conductors to the electrical apparatus.
Thus, in an example embodiment of the present disclosure, there is sensed:
(i) a first difference between LIVE and NEUTRAL;
(ii) a second difference between NEUTRAL and EARTH, and also (ill) a third phase difference between LIVE and NEUTRAL;
wherein electrical power is disconnected from an electrical apparatus in an event of [(i)], [(i) and (ii)], [(i) and (Hi)], or [(I), (ii) and (Hi)] exceeding one or more pre-set thresholds.
Embodiments of the present disclosure are of advantage in that it is feasible to eliminate, or at least partially address, the aforementioned problems in the prior art, in a cost-efficient and robust manner.
-7Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments construed in conjunction with the appended claims that follow.
It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
FIG. 1 is a block diagram of various operating areas in a three-phase electrical power supply;
FIG. 2 is a block diagram of an electrical system in which an electrical protection device is implemented, in accordance with an embodiment of the present disclosure;
FIG. 3 is a block diagram of an electrical system in which an electrical vehicle charging system is implemented, in accordance with an embodiment of the present disclosure;
-8FIGs. 4A and 4B are circuit diagrams of an electrical system in which an electrical vehicle charging system is implemented, in accordance with an embodiment of the present disclosure; and
FIG. 5 is a flow chart depicting steps of a method for (of) operating an electrical protection device, in accordance with an embodiment of the present disclosure.
In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
DETAILED DESCRIPTION OF EMBODIMENTS
The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.
In one aspect, the present disclosure provides the present disclosure provides an electrical protection device that, when in operation, controls electrical power coupled therethrough to an electrical apparatus, wherein the electrical protection device includes a matrix switching arrangement whose power switches are controlled from a data processing arrangement,
-9wherein the electrical power is coupled from the electrical protection device to the electrical apparatus via at least LIVE, NEUTRAL and EARTH conductors, and wherein the data processing arrangement senses, when in operation, a voltage difference between the LIVE and NEUTRAL conductors, and switches the switching matrix arrangement to disconnect the LIVE, NEUTRAL and EARTH conductors coupled to the electrical apparatus in an event that the voltage difference reduces below a threshold voltage (Vth) in magnitude.
Optionally, the electrical apparatus is an outdoors electrical apparatus, for example a garden tool, an electric lawnmower, an exterior lighting fitting, a (do-Zt-yourse/f) DIY hand tool, an outdoor industrial item of equipment, an air-conditioning apparatus, an outdoor heating fixture, an air compressor, an electrical vehicle charging system but not limited thereto.
Optionally, the switching matrix arrangement is implemented using electro-mechanical actuators. Optionally, as a safety feature, the switching matrix is implemented so that its electro-mechanical actuators move to an OPEN (OFF) state in an event of electrical power to operate the electrical protection device being interrupted, thereby isolating the electrical apparatus. Moreover, optionally, in the switching matrix arrangement, a series of a plurality of electro-mechanical contactors is employed for at least each of the LIVE and NEUTRAL conductors, so that the switching matrix arrangement of the electrical protection device is able to isolate its electrical apparatus in an event that one of the electrical contactors suffers a contact weld event; more optionally, to reduce contact wear, when such a plurality of electro-mechanical contactors is employed for at least each of LIVE and NEUTRAL conductors, a first electro-mechanical contactor of the plurality of electro-mechanical
- 10contactors is maintained in a CLOSED (ON) state when in operation, whereas a second contactor of the plurality of electro-mechanical contactors is switched to control electrical energy that is supplied to the electrical apparatus; in an event of a fault being detected the electrical protection device, both of the first and second electro-mechanical contactors are more to their OPEN (OFF) state.
Optionally, in addition to the electrical protection device providing protection is respect of the electrical apparatus, the switching matrix arrangement is also used for controlling power, in a manner of dual purpose use; for example, the switching matrix arrangement is used synergistically both for providing protection and switching-off of power, for example when pre-heating the electrical apparatus implemented as a garden sauna or outdoor bubble bath (for example, in a manner of remote switching for outdoor devices and installations).
Optionally, the electrical apparatus is an electrical vehicle charging system that, when in operation, controls electrical power coupled therethrough to an electrical vehicle to charge a battery arrangement of the electrical vehicle.
Embodiments of the present disclosure are concerned with protecting users from an electrical shock risk when using electrical apparatus, for example when using exterior electrical apparatus such as outdoor heated baths, DIY power tools, lawnmowers, outdoor lighting fixtures, outdoor audio sound systems, outdoor video projection systems, outdoor electrical vehicle chargers to charge battery arrangements of electrical vehicles, but not limited thereto; the embodiments function to provide protection, for example, in an event of a fault occurring with a NEUTRAL conductor of electrical power to which the electrical apparatus is connected.
-11 Moreover, embodiments of the present disclosure are concerned with protecting users and their electrical apparatus in an event of an electrical power grid overload that causes a given phase of an electrical supply grid to reduce significantly in magnitude relative to its usual nominal magnitude; such an overload is also manifested in a reduced voltage difference between the NEUTRAL and LIVE conductors.
Embodiments of the present disclosure provide an extremely costeffective and compact approach to provide user-protection against faults in the electrical apparatus.
The electrical protection device as described in the present disclosure provides a protection against risks associated with electrical shock and electrocution. Specifically, the electrical protection device prevents conduction of leakage electrical energy from uninsulated parts such as a metal body of an electrical apparatus, for example metal bodywork of an electrical vehicle, for example in an event of a connection fault, or both. In this regard, the electrical protection device switches the LIVE conductor, the NEUTRAL conductor and the EARTH conductor at any moment during a period of supplying electrical power to the electrical apparatus, in an event of a fault being detected by the electrical protection device.
Beneficially, the electrical protection device enables an identification of a fault in a NEUTRAL connection supplying the electrical protection device, in a compact and economical way. Notably, a fault in a NEUTRAL connection to an electrical protection device connected to an electrical apparatus is detected by using the LIVE conductor as a reference potential. Moreover, additionally, the electrical protection device detects a fault due to phase shift, for example between LIVE and NEUTRAL conductors; a fault is detected when the phase shift exceeds a phase threshold Θτη, or a temporal rate of change of the phase shift exceeds a differential phase rate threshold d(0TH)/dt, or both. The phase threshold
- 12Θτη is, for example, in a range of 5 degrees to 20 degrees in magnitude, more optionally in a range of 12 degrees to 18 degrees in magnitude, and yet more optionally in a range of 14 degrees to 17 degrees in magnitude, and yet more optionally substantially 15.5 degrees in magnitude.
As aforementioned, the electrical protection device substantially reduces, for example eliminates, a risk of an electrical shock, in a situation case of a fault occurring in respect of the source of electrical power, for example a fault in its NEUTRAL conductor to the electrical protection device. It will be appreciated that in the event of the fault occurring in the electrical power, a conductive shell or bodywork of the electrical apparatus (for example, a conductive shell of an electrical vehicle) potentially attains dangerously high potentials relative to a LOCAL EARTH, thereby presenting a risk of electric shock to users, or possibly electrocution upon contact of a user with the electrical apparatus.
As used herein, the term electrical apparatus refers to an electronic apparatus that requires electrical energy (namely, electricity) for functioning and use thereof. Specific examples of such electrical apparatus if provided elsewhere in this disclosure, for example outdoors electrical apparatus.
The electrical protection device includes a matrix switching arrangement, as aforementioned. Herein, the term matrix switching arrangement refers to an arrangement of electrical components that allows for connection or disconnection of the electrical apparatus from the electrical power; for example, the electrical components are implemented as electro-mechanical contactors, or similar. Optionally, semiconductor power devices such as Silicon Carbide FET's are employed in addition to provide an additional degree of protection, as such semiconductor devices can potentially switch in a few microseconds or less, to protect users. An electro-mechanical contactor is, for example, implemented to include a solenoid coil to establish a magnetic field when current flows in the
- 13solenoid coil, wherein the magnetic field actuates contacts of a switch to be drawn together by action of the magnetic field to provide a power connection through the contacts; when current is interrupted to the solenoid coil, the contacts spatially separate and break the power connection. Optionally, the matrix switching arrangement operates manually or automatically to provide a closed connection for providing electrical energy from the electrical protection device to the electrical apparatus, when the electrical protection device detects that there is an absence of any fault condition, as aforementioned.
Specifically, the power switches enable connection of the at least one of the LIVE conductor, the NEUTRAL conductor, the EARTH conductor, with the electrical apparatus. It will be appreciated that a power switch has a power ON' state and a power OFF' state, wherein the ON' state allows for conduction of electrical energy therethrough and the OFF' state prevents the conduction of electrical energy therethrough. For the LIVE conductor and the NEUTRAL conductor, it is beneficial that each of these is provided with a plurality of power switches connected in series such that the electrical apparatus can be isolated, even in an event that one of the power switches should fail in an ON' state (for example, due to contact weld occurring in an event of a power surge occurring). More optionally, the plurality of power switches for each of LIVE and NEUTRAL conductors is implemented as two power switches connected in series. However, it will be appreciated that more than two power switches can be coupled in series where there is a need for ultra-reliability in the electrical protection device.
Throughout the present disclosure, the term data processing arrangement refers to a computational element that is operable to respond to and processes instructions so as to connect or disconnect the electrical protection device to the electrical apparatus; moreover, the computational element also includes a sensing arrangement, for example
- 14including an analog-to-digital converter arrangement, that enables the computational element to acquire a measure of a voltage difference between the LIVE and NEUTRAL conductors within the electrical protection device, optionally also between the NEUTRAL and EARTH conductors within the electrical protection device, optionally a phase difference between the LIVE and NEUTRAL conductors within the electrical protection device (for example, using a phase-locked-loop or quadrature phase detector, for example implemented in software). Optionally, the data processing arrangement includes, but is not limited to, a microprocessor, a microcontroller, a complex instruction set computing (CISC) microprocessor, a reduced instruction set (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, or any other type of data processing circuit; for example, the electrical protection device is implemented using custom-designed digital hardware, ASIC or similar electronic components. Furthermore, the data processing arrangement refers to one or more individual processors, processing devices and various elements associated with a processing device that may be shared by other processing devices. Additionally, the one or more individual processors, processing devices and elements are arranged in various architectures for responding to and processing the instructions that govern an operation of the electrical protection device. In addition, the data processing arrangement comprises a sensor arrangement, as aforementioned, that senses, when in operation, various parameters related to the electrical power arrangement, the electrical apparatus and the electrical protection device. Specifically, the sensor arrangement includes at least one of: a voltage sensor, a current sensor, temperature sensors, a state-of-charge sensor, a phase sensor.
Optionally, the data processing arrangement is manually controlled using a control instruction from a user, a computing device, a control power flow; for example, the electrical protection device is reset by the user by pressing a button that resets the data processing arrangement. More
- 15optionally, the data processing arrangement is automatically controlled based on sensed signals. Optionally, the electrical protection device is provided with a user-viewable control panel providing an indication of whether or not a fault has been detected, and whether or not the electrical protection device has had to act, when in operation, to disconnect its electrical apparatus.
The term electricalpower refers to a source of electrical power, namely an arrangement that provides an electrical supply (specifically, electrical energy) to the electrical apparatus. In an example, the electricalpower refers to an electrical supply grid system, for example, a national electricity grid system, that provides electrical energy; the electrical supply grid system is beneficially coupled via one or more power transformers to the electrical protection device. Optionally, the source of electrical power provides AC electrical energy therefrom, for example AC at a nominal frequency of 50.0 Hz and at a nominal amplitude in a range of 191 Volts AC to 253 Volts AC. More optionally, the AC electrical energy is supplied as a single phase-supply, for example at a nominal grid frequency of 50.0 Hz (Europe) or 60.0 Hz (USA). Most domestic outdoor apparatus is single-phase, and limited to a maximum power in a range of 11 kW to 22 kW for electrical vehicle chargers, although a nominal charging power of approximately 7 kiloWatt is more usual for such electrical vehicle chargers.
The electrical protection device is beneficially included as an integral part of an electrical vehicle charger, or electrical vehicle charging system, wherein the aforementioned electrical apparatus to which electrical energy is supplied is an electrical vehicle including a rechargeable battery arrangement, a rechargeable ultracapacitor arrangement, or a combination thereof. The electrical power, coupled via the electrical vehicle charger to the electrical vehicle, includes at least LIVE, NEUTRAL
- 16and EARTH conductors to convey electrical energy to the electrical apparatus.
Referring to FIG. 1, there is shown an illustration of various operating areas in a three-phase electrical power supply, wherein three-phase electrical power supply has three phases, denoted by LI, L2 and L3; the illustration is indicated generally by 10. Such a three-phase supply is typically provided from a local power transformer in a given housing estate; each house of the given housing estate is typically supplied with a single-phase connection to the local power transformer; thus, a given house is provided with one of these phases, for example the phase LI that is a LIVE connection. Moreover, the given house is also provided with a NEUTRAL connection to the local power transformer. The local power transformer is also provided with a ground connection, referred to as a REMOTE EARTH. Thus, the given house is provided with a LIVE connection to phase LI, and a NEUTRAL connection. It will be appreciated that other houses in the given housing estate are connected to the phases L2 and L3, such that each of the phases is approximately equally loaded.
A central operating point 20 denotes a potential of the NEUTRAL in an event that the three phases LI, L2 and L3 are mutually matched in power loading. By national regulations, a circle 30 defines a 6 Volt AC limit that the NEUTRAL is permitted to attain relative to a local ground connection at the given house relative to a local ground connection at the given house, namely its LOCAL EARTH, in an event that a mismatch in loading between the phases LI, L2 and L3 arises in practice. However, for user safety, a circle 40 denotes a safety limit that the NEUTRAL connection is permitted to attain in an event of a fault condition arising; this limit is nominally 70 Volts AC relative to the LOCAL EARTH. It will be appreciated that the LOCAL EARTH is optionally implemented as a Protective Multiple Earthing (PME); PME is achieved, for example, by connecting to conductive metal objects buried in ground, to metal pipes
- 17of plumbing systems that penetrate ground, and so forth. Moreover, in the illustration 10 of FIG. 1, lines 6O(L1), 60(L2) and 60(L3) represent operating conditions when the LIVE and NEUTRAL connections are inphase, where areas of the illustration 10 remote from the lines 6O(L1), 60(L2) and 60(L3) correspond to operating regions wherein the LIVE and NEUTRAL connections are not in-phase. The LIVE connection, in use, potentially has a voltage in a range of 191 Volts AC to 253 Volts AC, depending on total loading on the phases LI, L2 and L3. In an event that a fault develops in the NEUTRAL connection between the given house and the local power transformer, a problem arises in that return current passes from the LOCAL GROUND via ground to the REMOTE EARTH. When such a fault occurs, the NEUTRAL connection at the given house can attain a dangerously high potential, for example in excess of 70 Volts AC. When the LIVE and NEUTRAL connections are not mutually in phase, an even greater hazard can potentially arise. For example, a phase shift of substantially 15 degrees between the LIVE and NEUTRAL connections at the given house can correspond to a dangerous operating condition. A peripheral outline 50 in FIG. 1 defines a limit of potential of the three phases LI, L2 and L3 in an event of there arising a phase difference between LIVE and NEUTRAL at the given house; when a phase difference of more than circa 15 degrees in magnitude arises, a potentially hazardous condition can arise.
However, a NEUTRAL connection fault, for example denoted by 380 in FIG. 3, potentially results in the NEUTRAL connection within the electrical protection device deviating from the REMOTE EARTH, for example when appreciable current flows from the LIVE connection via the electrical apparatus and then via the LOCAL EARTH through ground to the REMOTE EARTH at the local power transformer and therefrom to the NEUTRAL at the local power transformer. It will be appreciated from the foregoing that the EARTH connection at the given house is provided at a spatial vicinity of the electrical protection device (LOCAL EARTH), whereas an
- 18EARTH connection is provided also at the local power transformer (REMOTE EARTH), as shown in FIG. 3.
Specifically, a given EARTH connection, when correctly implemented, offers a very low electrical resistance to provide a path for flow of the electrical energy to the ground. It will be appreciated that the EARTH conductor enables conduction of any leakage electrical energy from the electrical apparatus to the ground in an event of a fault arising such as a short of the LIVE connection to a conductive exterior casing of the apparatus, thereby preventing a risk of serious electric shock to a user.
As illustrated in FIG. 3, the LOCAL EARTH refers to a conductor that is present locally, in other words, in proximity to the electrical protection device. In this regard, a metallic conducting plate is positioned in close proximity of the electrical protection device and buried into ground, for example into soil, for example via a conductive frame or plumbing system of a given building. Optionally, the metallic plate is positioned at a distance of 10 feet (circa 3 metres) from the electric protection device. Moreover, the REMOTE EARTH refers to a more substantial conductor that provides a common grounding point. In this regard, the REMOTE EARTH provides a common grounding point to each of connections from, for example, a national grid, a distribution substation, and the like.
Optionally, the LOCAL EARTH connection is implemented as a Protective Multiple Earthing (PME). In this regard, the NEUTRAL conductor and the EARTH conductor are connected via a shortest route to a LOCAL EARTH at premises of the given house, namely spatially close to the electrical protection device.
The data processing arrangement, when in operation, senses (namely, determines), for example, a voltage difference between LIVE and NEUTRAL conductors at the given house. In this regard, the data processing arrangement measures a voltage developed between the LIVE
- 19conductor and the NEUTRAL conductor ofthe electrical power received at the electrical protection device; such a measurement is, for example, achieved via use of resistor networks and analog differential amplifiers to provide an analog signal that is then digitized and processed by the data processing arrangement.
As aforementioned, the LIVE conductor assumes, when in operation, a potential in a range of 191 Volts (AC) to 253 Volts (AC) relative to the LOCAL EARTH. Moreover, the NEUTRAL conductor, when in operation, assumes a voltage that is normally within a range of 0 Volts to 6 Volts (AC), relative to the LOCAL EARTH. Therefore, in normal non-fault operating conditions, there is a substantial voltage difference between the LIVE and NEUTRAL conductors (namely, connections), generally in a range of 191 Volts to 253 Volts (AC). It will be appreciated that a substantial decrease in such voltage difference between the LIVE and NEUTRAL conductors indicates either a severe overloading of a given phase supplying the LIVE and NEUTRAL conductors of the electrical protection device, or a fault in the NEUTRAL conductor (for example, as a result of the aforementioned fault 380 occurring). Specifically, the decrease in the voltage difference between the LIVE and NEUTRAL conductors is caused by a substantial increase of voltage of the NEUTRAL conductor relative to the REMOTE EARTH. Consequently, such a fault in the NEUTRAL conductor presents a potential risk of electric shock through the electrical apparatus (for example, an outdoor electrical device such as an electrical vehicle charger, but not limited thereto) connected via the electrical protection device to the electrical power. For safety, the NEUTRAL connection must not exceed 70 Volts (AC) relative to the REMOTE EARTH, otherwise a hazardous situation arises for users.
Therefore, the data processing arrangement switches the switching matrix arrangement to disconnect the power switches coupled to the electrical apparatus in an event that the voltage difference reduces below
-20a threshold voltage (Vth) in magnitude. Herein, the disconnection of the power switches coupled to the electrical apparatus stops a supply of the electrical power thereto. Beneficially, such disconnection of the electrical apparatus from the electrical power eliminates the risk of electric shock therefrom. Herein, the term threshold voltage refers to a value of voltage difference between the LIVE conductor and the NEUTRAL conductor at the electrical protection device, below which the power switches coupled to the electrical apparatus are disconnected.
Optionally, as the threshold voltage (Vth) is in a range of 191 Volts (AC) to 253 Volts (AC); more optionally, the threshold voltage (Vth) is substantially 191 Volts (AC). A LIVE conductor voltage of 253 Volts AC and a NEUTRAL voltage of 70 Volts AC results in a voltage difference between LIVE and NEUTRAL of 183 Volts AC, that is less than the aforesaid range of 191 Volts (AC) to 253 Volts (AC), and would be detected by the electrical protection device as being a fault condition, requiring disconnection of the electrical apparatus from the electrical protection device.
In an example embodiment, the data processing arrangement further determines, when in operation, a voltage difference between NEUTRAL and EARTH conductors at the electrical protection device. As aforementioned, the NEUTRAL conductor potentially assumes a voltage in a range of 0 Volts to 40 Volts (AC) relative to the REMOTE EARTH. Similarly, the LOCAL EARTH conductor potentially assumes a voltage in a range of 0 Volta to 20 Volts (AC) relative to the REMOTE EARTH. Therefore, the NEUTRAL and EARTH connections (conductors) at the electrical protections device generally assume a negligible voltage therein when there is an absence of a fault. Hence, a substantial increase in such voltage difference between the NEUTRAL and EARTH conductors indicates a fault in at least one of: the NEUTRAL conductor, or the EARTH conductor (for example, an unreliable LOCAL EARTH). Therefore, the data
-21 processing arrangement beneficially switches the switching matrix to disconnect the power switches coupled to the electrical apparatus in an event that the voltage difference increases above an earth threshold voltage (Vet) in magnitude. Herein, the term earth threshold voltage (Vet) refers to a value of voltage difference between the NEUTRAL conductor and the EARTH conductor above which the power switches coupled to the electrical apparatus are disconnected.
Optionally, the earth threshold voltage (Vet) is in a range of 0 Volts to 40 Volts (AC), and more optionally substantially 6 Volts (AC). Alternatively, yet more optionally, the earth threshold voltage (Vet) is substantially 20 Volts (AC).
Optionally, the data processing arrangement switches the switching matrix arrangement to disconnect the power switches coupled to the electrical apparatus in an event that the phase shift changes above a threshold phase shift in magnitude (6th); for example, the threshold phase shift in magnitude (Θτη) is in a range of 5 degrees to 20 degrees in magnitude, more optionally in a range of 12 degrees to 18 degrees in magnitude, and yet more optionally in a range of 14 degrees to 17 degrees in magnitude, and yet more optionally substantially 15.5 degrees in magnitude. Herein, the term threshold phase shift refers to a magnitude of the phase shift between the LIVE and NEUTRAL conductors above which the power switches coupled to the electrical apparatus are disconnected by the electrical protection device.
Optionally, the electrical protection device monitors for potential fault conditions through a period during which power is supplied via the electrical protection device to the electrical apparatus; such monitoring can be periodic, alternatively substantially continuously in real-time, for example at 0.5 second intervals. The matrix switching arrangement is used to connect the electrical apparatus for providing electrical energy thereto at a beginning of the duration of supply of electrical energy to the
-22electrical apparatus, and to disconnect the electrical apparatus at an end of the duration of supply of electrical energy to the electrical apparatus. For example, the period of supply refers to a time period in which the electrical apparatus is operated, for example when being used for a task of recharging an electrical battery arrangement of an electrical vehicle. More optionally, throughout the duration of supply to the electrical apparatus, there is undertaken periodical or continuous monitoring of voltage differences, optionally also phase differences, in at least the LIVE, NEUTRAL and EARTH conductors at the electrical protection device.
Optionally, the electrical protection device is arranged for the matrix switching arrangement to operate within a time duration of less than 5 seconds upon sensing a fault, more optionally in a time duration of less than 1 second. Specifically, the data processing arrangement detects a fault upon sensing a voltage difference lower than the threshold voltage (Vth) between the LIVE conductor and the NEUTRAL conductor, for example in an event of a fault being detected, for example the fault 380. Subsequently, the data processing arrangement provides control instructions to the matrix switching arrangement to disconnect the power switches, thereby isolating the electrical apparatus upon sensing the reduction of voltage difference below the threshold voltage (Vth) lasting for more than 5 seconds, more optionally for more than 1 second.
The electrical protection device as aforementioned is beneficially employed in an electrical vehicle charging system that includes an electrical vehicle charger; a given electrical vehicle has an on-board inverter and battery management system that manage actual battery recharging, whereas an electrical vehicle charger is a term used to refer to a connection arrangement that allows the on-board inverter and battery management system to be coupled to an electrical power grid.
In an implementation, the electrical vehicle charger is a plug-in charger, wherein the electrical vehicle is plugged into the electrical vehicle charger
-23via a flexible charging cable. Optionally, the electrical vehicle charger is an integrated infrastructure comprising a hardware charging source, cloud services (for example, an Internet® connection), and/or user devices having graphical user-interface therein. Such user devices enable interaction of a user (for example, an owner of the electrical vehicle, a service provider operating the electrical vehicle charging system) with the electrical vehicle charging system.
Optionally, the threshold voltage (Vth) for the electrical protection device of the electrical vehicle charging system is in a range of 191 Volts to 253 Volts (AC), as aforementioned. More optionally, the threshold voltage (Vth) is substantially 191 Volts (AC), as aforementioned.
Optionally, the data processing arrangement further, when in operation, senses, namely determines or monitors, a voltage difference between the NEUTRAL and EARTH conductors, and switches the switching matrix arrangement to disconnect the LIVE, NEUTRAL and EARTH conductors coupled to the electrical vehicle in an event that the voltage difference increases above an earth threshold voltage (Vet) in magnitude. Optionally, the earth threshold voltage (Vet) is in a range of 0 Volts to 40 Volts (AC). More optionally, the earth threshold voltage (Vet) is substantially 6 Volts (AC) for improved safety, alternatively substantially 20 Volts (AC) to provide a more robust margin against accidental tripping out of the electrical protection device (for example, in an event of significant electrical power grid noise, for example power surges caused by lightning and similar).
Optionally, the data processing arrangement senses, namely determines, when in operation, a phase difference between the LIVE and NEUTRAL conductors, and switches the switching matrix to disconnect the LIVE, NEUTRAL and EARTH conductors coupled to the electrical vehicle in an event that the phase shift changes above a threshold phase shift (0th) in magnitude, for example as aforementioned.
-24DETAILED DESCRIPTION OF THE DRAWINGS
Referring to FIG. 1, this illustration 10 has been described in the foregoing, to elucidate operating regimes for the electrical apparatus in which user hazard can occur.
Referring next to FIG. 2, there is shown a block diagram of a system 100 in which an electrical protection device 102 is implemented, in accordance with an embodiment of the present disclosure. A source of electrical power 104 is coupled via the electrical protection device 102 to an electrical apparatus 106, to provide electrical energy to the electrical apparatus 106. The electrical protection device 102, when in operation, controls electrical energy drawn from the source of electrical power 104. The electrical protection device 102 includes a matrix switching arrangement 108 whose power switches 110 are controlled from a data processing arrangement 112. The source of electrical power 104 provides at least LIVE, NEUTRAL and EARTH conductors (also referred to as connections) via the electrical protection device 102. The data processing arrangement 112 senses (namely, determines), when in operation, a voltage difference between LIVE and NEUTRAL conductors, and switches the matrix switching arrangement 108 to disconnect the power switches 110 coupled to the electrical apparatus 106 in an event that the voltage difference reduces below a threshold voltage (Vth) in magnitude. In normal operation, the LIVE conductor is in a range of 191 Volts (AC) to 253 Volts (AC) relative to a REMOTE EARTH at the source of electrical power 104. Moreover, a hazardous situation arises when the NEUTRAL conductor is more than 70 Volts (AC) relative to a LOCAL EARTH in a proximity of the electrical protection device 102, mutatis mutandis the electrical apparatus 106.
In will be appreciated that the electrical apparatus 106 is an outdoor electrical apparatus, for example an outdoor garden fixture, a DIY power
-25tool, an electrical lawnmower, an externally-mounted air-conditioning unit, an electrical vehicle charging system and so forth. The electrical protection device 102 is beneficially used as a component to implement an electrical vehicle charging system, for denoted by 202 in FIG. 3.
Referring next to FIG. 3, there is shown a block diagram of a system 200 in which an electrical protection device as aforementioned is implemented; for example, the system 200 is implemented as an electrical vehicle charging system 202, in accordance with an embodiment of the present disclosure. A source of electrical power 204 is coupled through the electrical vehicle charging system 202 to an electrical vehicle 206, to charge a battery arrangement 208 of the electrical vehicle 206. The electrical vehicle charging system 202, when in operation, controls power supplied from the source of electrical power 204 to the electrical vehicle 206. The electrical vehicle charging system 202 includes an electrical vehicle charger 210 including a matrix switching arrangement 212 whose power switches 214 are controlled from a data processing arrangement 216. The electrical power 204 includes at least LIVE, NEUTRAL and EARTH conductors that are coupled via the electrical vehicle charging system 202 for conveying power to the electrical vehicle 206. The data processing arrangement 216, when in operation, senses (namely determines):
(I) a voltage difference between LIVE and NEUTRAL conductors, and switches the switching matrix arrangement 212 to disconnect the power switches 214 coupled to the electrical vehicle 206 in an event that the voltage difference reduces below a threshold voltage (Vth) in magnitude. Optionally, the threshold voltage (Vth) is in a range of 191 Volts (AC) to 253 Volts (AC)
Optionally, the data processing arrangement 216, when in operation, additionally senses at least one of:
(ii) a voltage difference between NEUTRAL and EARTH conductors, and switches the switching matrix arrangement 212 to disconnect the power switches 214 coupled to the electrical vehicle 206 in an event that the voltage difference exceeds a threshold voltage (Vet) in magnitude; optionally, the threshold voltage (Vet) is substantially 6 Volts (AC), alternatively substantially 20 Volts (AC); and (iii) a phase difference between the LIVE and NEUTRAL conductor exceeds, or changes, by more than a threshold phase different (Θτη), and/or changes at a temporal rate that exceeds a rate of phase change threshold, d(0TH)/dt. Optionally, the threshold phase different (Θτη) is in a range of 12 degrees to 20 degrees, for example substantially 15 degrees.
Referring next to FIG. 4A, there is shown a circuit diagram 300 of a system 200 in which an electrical vehicle charging system 202 is implemented, in accordance with an embodiment of the present disclosure. A source of electrical power 204 includes at least LIVE, NEUTRAL and EARTH conductors, depicted as a LIVE conductor 302, a NEUTRAL conductor 304, and an EARTH conductor 306 (LOCAL EARTH). The source of electrical power 204 is coupled to an electrical vehicle 206 through the electrical vehicle charging system 202 to charge a battery arrangement 208 of the electrical vehicle 206. The electrical vehicle charging system 202, when in operation, controls electrical power provided from the source of electrical power 204. The electrical vehicle charging system 202 includes an electrical vehicle charger 210 including a matrix switching arrangement 212 whose power switches, depicted as the power switches 308, 310, 312, are controlled from a data processing arrangement 216. The data processing arrangement 216, when in operation, senses (namely, determines) a voltage difference between a LIVE conductor 302 and a NEUTRAL conductor 304, and switches the switching matrix to disconnect the power switches 308, 310, and 312
-27coupled to the electrical vehicle 206 in an event that the voltage difference reduces below a threshold voltage (Vth) in magnitude. It will be appreciated that the source of electrical power 204 is connected to a power grid system 314, such as a grid system, for example, a national power grid of a given country, and to ground 316 for earthing purposes (REMOTE EARTH). Indoor domestic appliances are denoted by a domestic load 318, for example filament lamps but not limited thereto.
Referring next to FIG. 4B, in an event that the LOCAL EARTH 306 and the REMOTE EARTH 316 become mutually disconnected by way of a disconnection fault 380 in a NEUTRAL connection, there is determined a voltage difference between the LIVE conductor 302 and the NEUTRAL conductor 304; when the voltage difference therebetween potentially exceeds the threshold voltage (Vth) in magnitude, for example when the LOCAL EARTH 306 has significant resistance, and the domestic load 318 (for example, a filament lamp) provides a path between the still connected LIVE conductor 302 and the NEUTRAL and the floating EARTH conductor downstream of the fault 380 while the electrical vehicle 206 is connected to the electrical vehicle charging system, a potentially hazardous situation arises. Such a voltage difference is potentially a considerable hazard if a given user touches a conductive body of the electrical vehicle 206, and the given user provides a conductive path to the LOCAL EARTH 306, for example when charging the electrical vehicle 206. Opening of the power switches 312, for example, removes a hazard of electrical shock when the disconnection fault 380 arises in operation.
Referring next to FIG. 5, there is shown a flow chart depicting steps of a method 400 for (of) operating an electrical system that includes an electrical safety device as described in the foregoing for reducing operating hazards, in accordance with an embodiment of the present disclosure. The electrical system, for example an electrical vehicle charging system, when in operation, controls electrical power coupled to
-28an electrical apparatus that consumes energy, for example an outdoor electrical apparatus, for example for recharging an electrical battery arrangement or ultracapacitor arrangement of an electrical vehicle. The method is depicted as a sequence of steps in a logical flow diagram, wherein the sequence of steps can be implemented in hardware, software, or a combination thereof, for example as aforementioned.
At a step 402, an electrical system, for example an electrical vehicle charging system, is arranged to include an electrical protection device including a matrix switching arrangement whose power switches are controlled from a data processing arrangement, wherein a source of electrical power is coupled to the electrical apparatus via the power switches and wherein the source of electrical power includes at least LIVE, NEUTRAL and EARTH conductors for conveying electrical power to the electrical apparatus; optionally, the source of electrical power is implemented as a single-phase AC configuration. At a step 404, the data processing arrangement is arranged to determine, when in operation, a voltage difference between LIVE and NEUTRAL conductors, and to switch the matrix switching arrangement to disconnect the power switches coupled to the electrical apparatus in an event that the voltage difference reduces below a threshold voltage (Vth) in magnitude. Additionally, optionally, at the step 404, the data processing arrangement is arranged to determine, when in operation, a voltage difference between NEUTRAL and EARTH conductors, and to switch the matrix switching arrangement to disconnect the power switches coupled to the electrical apparatus in an event that the voltage difference exceeds a threshold voltage (Vet) in magnitude. Additionally, optionally, at the step 404, the data processing arrangement is arranged to determine, when in operation, a phase difference between NEUTRAL and LIVE conductors, and to switch the matrix switching arrangement to disconnect the power switches coupled to the electrical apparatus in an event that the phase difference exceeds a phase threshold (Θτη) or the phase difference temporally changes at a
-29rate that exceeds a temporally differential phase threshold d(0TH)/dt. For example, the threshold phase shift in magnitude (0th) is in a range of 5 degrees to 20 degrees in magnitude, more optionally in a range of 12 degrees to 18 degrees in magnitude, and yet more optionally in a range of 14 degrees to 17 degrees in magnitude, and yet more optionally substantially 15.5 degrees in magnitude. Herein, the term threshold phase shift refers to a magnitude of the phase shift between the LIVE and NEUTRAL conductors above which the power switches coupled to the electrical apparatus are disconnected by the electrical protection device. For example, the temporally differential phase threshold d(0TH)/dt is optionally set at in a range of 100 degrees per 100 millisecond (mSec) to 100 degrees per 100 mSec; it will be appreciated that a sudden disconnection of NEUTRAL between a LOCAL EARTH and a REMOTE EARTH can cause a sudden phase shift within one cycle of AC mains electricity, such that the electrical protection device is designed to detect such a one-off phase shift occurring a register within the data processing arrangement that a fault has occurred that potentially results in a hazardous operating situation in respect of the electrical apparatus.
The steps 402 and 404 are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein.
Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as including, comprising, incorporating, have, is used to describe and claim the present disclosure are intended to be construed in a nonexclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.

Claims (23)

1. An electrical protection device that, when in operation, controls electrical power coupled therethrough to an electrical apparatus to provide electrical energy thereto, wherein the electrical protection device includes a matrix switching arrangement whose power switches are controlled from a data processing arrangement, wherein electrical power is coupled from the electrical protection device to the electrical apparatus via at least LIVE, NEUTRAL and EARTH conductors, and wherein the data processing arrangement senses, when in operation, a voltage difference between the LIVE and NEUTRAL conductors, and switches the switching matrix to disconnect the LIVE, NEUTRAL and EARTH conductors coupled to the electrical apparatus in an event that the voltage difference reduces below a threshold voltage (Vth) in magnitude.
2. An electrical protection device of claim 1, wherein the threshold voltage (Vth) is in a range of 191 Volts to 253 Volts (AC).
3. An electrical protection device of claim 1 or 2, wherein the threshold voltage (Vth) is substantially 191 Volts (AC).
4. An electrical protection device of any one of the preceding claims, wherein the data processing arrangement further, when in operation, senses a voltage difference between the NEUTRAL and EARTH conductors, and switches the switching matrix to disconnect the LIVE, NEUTRAL and EARTH conductors coupled to the electrical apparatus in an
-31 event that the voltage difference increases above an earth threshold voltage (Vet) in magnitude.
5. An electrical protection device of claim 4, wherein the earth threshold voltage (Vet) is in a range of 0 Volts to 40 Volts (AC).
6. An electrical protection device of claim 5, wherein the earth threshold voltage (Vet) is in a range of 0 Volts to 6 Volts (AC).
7. An electrical protection device of any one of the preceding claims, wherein the data processing arrangement senses, when in operation, a phase difference between the LIVE and NEUTRAL conductors, and switches the switching matrix to disconnect the LIVE, NEUTRAL and EARTH conductors coupled to the electrical apparatus in an event that the phase shift changes above a threshold phase shift (Θτη) in magnitude.
8. An electrical protection device of any one of the preceding claims, wherein the matrix switching arrangement is used to connect the electrical apparatus for providing electrical energy at least at a beginning of an operating duration of the electrical apparatus, and to disconnect the electrical apparatus at least at an end of the operation duration of the electrical apparatus.
9. An electrical protection device of claim 8, wherein the electrical protection device senses a fault condition arising during the operating duration and isolates the electrical apparatus in an event of a fault arising during the operating duration, wherein the sensing is implemented in a periodic or continuous manner.
10. An electrical protection device of any one of the preceding claims, wherein the power switches are implemented using electro-mechanical contactors.
11. An electrical vehicle charging system that, when in operation, controls electrical power coupled therethrough to an electrical vehicle to charge a battery arrangement of the electrical vehicle, wherein the electrical vehicle charging system includes an electrical protection device of any one of the preceding claims, wherein the electrical protection device includes a matrix switching arrangement whose power switches are controlled from a data processing arrangement, wherein electrical power is coupled to the electrical vehicle via at least LIVE, NEUTRAL and EARTH conductors, and wherein the data processing arrangement senses, when in operation, a voltage difference between the LIVE and NEUTRAL conductors, and switches the switching matrix to disconnect the LIVE, NEUTRAL and EARTH conductors coupled to the electrical vehicle in an event that the voltage difference reduces below a threshold voltage (Vth) in magnitude.
12. An electrical vehicle charging system of claim 11, wherein the threshold voltage (Vth) is in a range of 191 Volts to 253 Volts (AC).
13. An electrical vehicle charging system of claim 11 or 12, wherein the threshold voltage (Vth) is substantially 191 Volts (AC).
14. An electrical vehicle charging system of any one of the claims 11 to
13, wherein the data processing arrangement further, when in operation, senses a voltage difference between the NEUTRAL and EARTH conductors, and switches the switching matrix to disconnect the LIVE, NEUTRAL and EARTH conductors coupled to the electrical vehicle in an event that the voltage difference increases above an earth threshold voltage (Vet) in magnitude.
15. An electrical vehicle charging system of claim 14, wherein the earth threshold voltage (Vet) is in a range of 0 Volts to 40 Volts (AC).
16. An electrical vehicle charging system of claim 14 or 15, wherein the earth threshold voltage (Vet) is substantially 6 Volts (AC).
17. An electrical vehicle charging system of any one of the claims 11 to
16, wherein the data processing arrangement senses, when in operation, a phase difference between the LIVE and NEUTRAL conductors, and switches the switching matrix to disconnect the LIVE, NEUTRAL and EARTH conductors coupled to the electrical vehicle in an event that the phase shift changes above a threshold phase shift (Θτη) in magnitude.
18. An electrical vehicle charging system of any one of the claims 11 to
17, wherein the matrix switching arrangement is used to connect the electrical vehicle for charging at least at a beginning of a charging cycle, and to disconnect the electrical vehicle at least at an end of the charging cycle.
19. An electrical vehicle charging system of any one of the claims 11 to
18, wherein the power switches are implemented using electromechanical contactors.
20. A method for (of) operating an electrical protection device that, when in operation, controls electrical power coupled therethrough to an electrical apparatus, characterized in that the method includes:
(i) arranging for the electrical protection device to include a matrix switching arrangement whose power switches are controlled from a data processing arrangement, wherein electrical power is coupled to the electrical apparatus via the power switches and wherein the electrical power includes at least LIVE, NEUTRAL and EARTH conductors, and (ii) arranging for the data processing arrangement to sense, when in operation, a voltage difference between the LIVE and NEUTRAL
-34conductors, and to switch the matrix switching arrangement to disconnect the power switches coupled to the electrical apparatus in an event that the voltage difference reduces below a threshold voltage (Vth) in magnitude.
21. A method for (of) operating an electrical protection device of claim 20, wherein the method further includes arranging the data processing arrangement, when in operation, to sense a voltage difference between the NEUTRAL and EARTH conductors, and to switch the matrix switching arrangement to disconnect the power switches coupled to the electrical apparatus in an event that the voltage difference increases above an earth threshold voltage (Vet) in magnitude.
22. A method for (of) operating an electrical protection device of any one ofthe claims 20 to 21, wherein the method further includes arranging the data processing arrangement, when in operation, to sense a phase difference between the LIVE and NEUTRAL conductors, and to switch the matrix switching arrangement to disconnect the power switches coupled to the electrical apparatus in an event that the phase shift changes above a threshold phase shift (Θτη) in magnitude.
23. A computer program product comprising a non-transitory computer-readable storage medium having computer-readable instructions stored thereon, the computer-readable instructions being executable by a computerized device comprising processing hardware to execute the method of claim 20, 21 or 22.
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GB2601154A (en) * 2020-11-19 2022-05-25 Indra Renewable Tech Ltd Electric vehicle supply equipment
GB2601154B (en) * 2020-11-19 2023-06-07 Indra Renewable Tech Ltd Electric vehicle supply equipment
GB2603191A (en) * 2021-02-01 2022-08-03 Siemens Mobility Ltd Open-neutral electrical fault isolator
GB2603191B (en) * 2021-02-01 2023-05-24 Yunex Ltd Open-neutral electrical fault isolator
WO2024009103A1 (en) * 2022-07-06 2024-01-11 Greentec International Limited Voltage-based disconnection of electric vehicle supply equipment
GB2623530A (en) * 2022-10-18 2024-04-24 Juuce Ltd Fault detection module for an electrical supply system

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